Self-retained threaded nuts, which can be installed prior to the insertion of the bolt or stud, have been of the type designed for axial loading only. For example, in U.S. Pat. No. 2,982,989, a flexible metal ply nut is adapted to be squeezed into the hollow stem of a cabinet knob or pull and, upon installation of the threaded fastener, an axial load is applied which straightens or flattens the flexible nut so that its edges will bite into the surrounding metallic wall of the hollow stem and provide a gripping action. The nut is located or centered by the surrounding stem walls bearing against the edges of the ply nut; this is not always a reliable centering mechanism due to the freedom of the nut to skew within the stem. This type of construction is capable of withstanding principally axial loads (that is, loads that are in the direction of the axis of the bolt or threaded stud) and is effective only when working with metallic members which are to be assembled, such as the hollow shank of the knob and the metallic wall of the drawer or door to which the knob is attached.
Similarly, in U.S. Pat. No. 1,547,628, an oversize sheet metal nut is adapted to be squeezed between metallic cast iron lugs that are cast on a cast iron wall, the sheet metal nut then being ready for reception of a threaded fastener when inserted into its central opening. Again the lugs act to hold the outer edges of the nut so that a screw may be torqued therein, but the manner of holding can sometimes lead to mislocation by skewing. The fastener assembly is adapted to withstand axial loading only and will not endure transverse loading because of the flexibility of the nut itself.
In U.S. Pat. No. 971,976, a nut is designed for placement on one of the members of the assembly prior to insertion of the bolt. Two legs or fingers of the nut are inserted through a special shaped hole from one side of the part and staked over the opposite side of the part for retention. Transverse loading must be minimal because the fingers are adapted to engage ceramic sockets which will not withstand great force. The nut itself is not self-retained because it must be held in its turned position while inserting the bolt and threading the bolt therethrough; the nut does not fit securely in one part and can easily be dislodged from its station prior to threading.
What is needed is a nut construction which permits the nut to be easily installed by press-fitting onto planar mating surfaces in a self-retained condition on one of the parts to be assembled, which part can be nonperforated and made of plastic or nonmetal material. The nut should be able to cooperate with the part upon which it is assembled to transmit transverse loading; this is particularly important in assemblies for the automotive industry. The nut should be capable of being quickly installed in a fool-proof manner ready for reception of a threaded male member, the latter typically being carried by the mating part.